Japanese Fisheries Ministry councillor Akira Nakamae, revealed the plans while attending a Southern Bluefin Tuna conference in Christchurch this week. The move could spell the end of the IWC, which was set up to manage and conserve whale stocks.
Nakamae said Japan might set up an alternative organisation to the IWC to manage commercial whaling or join the North Atlantic Marine Mammal Commission (NAMMCO), which includes Norway, Iceland, Greenland, and the Faroe Islands, and extend its mandate to control whaling worldwide.
Nakamae said Japan would push for change at the IWC at the same time as moving to set up the rival organisation.
A decision would be made on which option to pursue before the next IWC meeting in Italy in July.
A spokesman for New Zealand Conservation Minister Chris Carter said the minister wondered how many countries would join any new international whaling organisation.
"Countries representing two thirds of the world's population supported whale conservation at the last meeting of the IWC," the spokesman said.
Nakamae said: "To be frank, we were very displeased at what happened at the IWC meeting in Berlin this year", referring to the IWC's decision at the meeting to establish a Conservation Committee, passed by 25 votes to 20.
The creation of the Conservation Committee, the focus on setting up whale sanctuaries, and stalling over the provision of a sustainable management plan for whaling by IWC members was frustrating to Japan.
"Japan's position is quite simple. We aggressively defend the position of conserving cetacean stocks, which are at risk. However, if the stocks are scientifically proven to be at quite a robust state we believe that as one of the natural resources it can be used sustainably," Nakamae said.
Nakamae said it was technically possible under the United Nations Convention on Law of the Sea (UNCLOS) to have several organisations managing marine mammal resources.